1. Field of the Invention
The present invention relates generally to semiconductor processing. More specifically, the present invention relates to a method for forming fully silicided gate electrodes in a semiconductor device.
2. Description of the Prior Art
As semiconductor technology advances, semiconductor devices are becoming increasingly smaller. However, this scaling down of devices may cause problems. For example, as gate oxides are scaled down, gate capacitance due to polysilicon depletion issues becomes more problematic, adversely affecting device performance.
One solution to this problem is the use of different metal gates for both NMOS and PMOS field effect transistors to serve as a replacement to polysilicon gates. However, the formation and integration of these dual metal gates are complex tasks as compared to form traditional doped polysilicon gates.
Instead of the formation of dual metal gates, one type of technology known today is to form a fully silicided (FUSI) gate electrode by using radiated heat during a rapid thermal annealing process to fully silicide a silicon layer.
FUSI gate electrode has attracted much attention recently as a promising metal gate candidate and has been studied widely for its simplified integration and tunable work function. However, it is still an issue to achieve real band-edge work function modulation.